1644142197 has 4 divisors (see below), whose sum is σ = 2192189600. Its totient is φ = 1096094796.

The previous prime is 1644142193. The next prime is 1644142223. The reversal of 1644142197 is 7912414461.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 1644142197 - 2² = 1644142193 is a prime.

It is a super-3 number, since 3×1644142197³ (a number of 29 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1644142193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 274023697 + ... + 274023702.

It is an arithmetic number, because the mean of its divisors is an integer number (548047400).

Almost surely, 2^1644142197 is an apocalyptic number.

It is an amenable number.

1644142197 is a deficient number, since it is larger than the sum of its proper divisors (548047403).

1644142197 is an equidigital number, since it uses as much as digits as its factorization.

1644142197 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 548047402.

The product of its digits is 48384, while the sum is 39.

The square root of 1644142197 is about 40548.0233426982. The cubic root of 1644142197 is about 1180.2657155608.

The spelling of 1644142197 in words is "one billion, six hundred forty-four million, one hundred forty-two thousand, one hundred ninety-seven".